Isolation and characterization of nuclear basic protein (protamine) from boar spermatozoa

Area of Science:

• Biochemistry
• Molecular Biology
• Reproductive Science

Background:

• Sperm nuclei contain DNA tightly packed by protamines.
• Understanding protamine structure is crucial for male fertility and DNA packaging.

Purpose of the Study:

• To isolate and purify boar sperm nuclei.
• To extract and characterize boar protamine.
• To investigate the structural heterogeneity of boar protamine.

Main Methods:

• Differential solubilization and sucrose gradient sedimentation for nuclei purification.
• Cold acid extraction and ion-exchange chromatography for protamine isolation.
• Gel filtration and chymotryptic digestion for protamine characterization.

Main Results:

• Purified boar sperm nuclei showed specific DNA, RNA, protein, and protamine ratios.
• Boar protamine molecular weight was estimated at 6600 Da.
• Protamine exhibited heterogeneity at the carboxy-terminal end, confirmed by peptide analysis.

Conclusions:

• A robust method for boar sperm nuclei and protamine isolation was established.
• Boar protamine possesses a defined amino terminus and heterogeneous carboxy termini.
• This structural heterogeneity may have implications for sperm function and male fertility.